Issue #2618500 by chx: Single on/off checkbox is always checked

better_exposed_filters_exposed_form_plugin.inc

@@ -1438,7 +1438,27 @@ dateFormat: "dd-mm-yy"
           $form[$filter_id]['#description'] = $options['more_options']['bef_filter_description'];
           $form[$filter_id]['#return_value'] = 1;
           $form[$filter_id]['#type'] = 'checkbox';
-
+          // Views populates missing values in $form_state['input'] with the
+          // defaults and a checkbox does not appear in $_GET (or $_POST) so it
+          // will appear to be missing when a user submits a form. Because of
+          // this, instead of unchecking the checkbox value will revert to the
+          // default. More, the default value for select values is reused which
+          // results in the checkbox always checked. So we need to add a form
+          // element to see whether the form is submitted or not and then we
+          // need to look at $_GET directly to see whether the checkbox is
+          // there. For security reasons, we must not copy the $_GET value.
+
+          // First, let's figure out a short name for the signal element and
+          // then add it.
+          if (empty($signal)) {
+            for ($signal = 'a'; isset($form[$signal]); $signal++);
+            // This is all the signal element needs.
+            $form[$signal]['#type'] = 'hidden';
+          }
+          $checked = isset($form_state['input'][$signal]) ? isset($_GET[$filter_id]) : $form[$filter_id]['#default_value'];
+          // Now we know whether the checkbox is checked or not, set #value
+          // accordingly.
+          $form[$filter_id]['#value'] = $checked ? $form[$filter_id]['#return_value'] : 0;
           // Handoff to the theme layer.
           $form[$filter_id]['#theme'] = 'checkbox';
           break;